There is a whole tradition of coffee in Singapore. It's quite fun. Delicious. And not at all expensive.
A Kopitiam is a coffee shop. There are some that you see everywhere:
ToastBox
Killiney
My favorite drink is: Kopi-C cosong
That is black coffee with condensed milk, and no sugar.
As I understand it, cosong is a malaysian word meaning 'empty' and in this context it means 'lite'
The kayatoast is good.
And most kopitiam will have some food items as well.
Softboiled eggs (called half-boiled in singapore) are popular.
I prefer a 'full boiled egg'
There are kopitiams in the airport, and in the new Jewel (landslide at Changi), as well as through out the city. You can't miss them.